Watching Gary Oldman's performance as Winston Churchill in Darkest Hour, it's hard to figure out where Oldman ends and Churchill begins. Through complex make-up effects (by genuine wizard Kazuhiro Tsuji) and whip-smart direction (by Joe Wright), Oldman, working from a craftily constructed screenplay (by Anthony McCarten), seamlessly brings a long dead historical figure to full-blooded life. But ultimately it rested on Oldman's shoulders to craft the character, which turned out to be a challenge is was more than up for.

"The characterization of Churchill had to come through," Oldman explained. "The emotion and intent and all of that, has to come through the make-up. The character has to be there." The actor insists that it "wasn't simply a matter of turning up and putting some rubber on and walking on set." Instead, he'd delved into the historical data, mining the richness of Churchill for his performance. "I'd done some research, watching footage and reading books, what you imagine getting ready for something like this."

But it wasn't just the historical research that got Oldman plugged into who Churchill was; he embraced all aspects of Darkest Hour. "By the time we started filming, I knew the film like a play. I didn't have to keep revisiting it every day." Contrary to what you might image, Oldman didn't have time to preview the day's work while sitting in the make-up chair as he (physically, at least) began his transformation. "I knew there wasn't time to look at the script and fidget and move around," Oldman told us. "I wanted all the words to be inside me. I wanted them in there to such a point that I didn't have to worry about it or think about it."

This kind of intimate knowledge of the material was a godsend for director Wright, who often had to choreograph elaborate camera movements or wrangle other actors elsewhere in the scene. In short, Oldman's encyclopedic appreciation meant Wright could "really direct him." Wright explained: "You're not dealing with someone not knowing what they're doing or trying to remember their lines. All of that's done. So you can really mine down into the meaning of the individual intentions and moments. And you're free."

It's that freedom that allowed Oldman and Wright to craft one of the most unforgettable performances this year. It's very much a victory.